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AEM EMS-4 - reversing PWM scale

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I have searched the webinars and forum for general intro to the EMS-4 but I can't find - if there is a webinar or course, please do let me know and I'll do my homework.

I'm setting up an AEM EMS-4 and need to configure the idle control on a 3SGTE.

The idle control operates as:

- if it has 0V, it is fully open (so revs rise)

- if it has +V, it will start to shut.

In the software this leads to a counter-intuitive setup where 0% duty is high rpm and 100% duty is low rpm. If I configure the calibration table with this, it plays havoc with the closed-loop feedback as it if sees the RPM is too high, and tries to lower, it lowers the %, which increases the RPM - the cycle loops until it hits the limits.

On the Motec M4 there was a setting on the PWM to say "100% = fully open" or "100% = fully closed" so you can flip the calibration. Is there something equivalent on the EMS-4?


After doing some more digging, I think I've found the answer. There is an option called "Idle Invert" which in the manual suggests it will do what I need - to make the rising % scale try to increase the RPM. Sadly I've left the car now so will have to try again another day... but hopefully this is it.

Tested this today and this invert setting does the job. All working properly now.

had exactly the same issue with the haltech base map for the k series (but with alternator control) and exactly the same fix :)

So much nicer when the settings are 0% = lowest not 0% is the highest - PID controls work much happier with things the right way around :)

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